Use of ionic liquids in catalysis is continuously becoming more attractive in chemical engineering. Supported ionic liquid catalyst (SILCA) consists of immobilized catalytic species, e.g. transition metal particles residing in an ionic liquid layer immobilized on a solid support. The effect of different ionic liquids in SILCA on activity and selectivity in selective hydrogenations has been studied and the catalysts have been characterized in detail. (c) 2007 Elsevier Ltd. All rights reserved.